DBoreA Olefination

There DBoreA Olefination is the transformation of 1, 2?diols into alkenes via the cis? (or syn?) elimination of cyclic thionocarbonate in the presence of dimethoxy or diethoxyphenylphosphite. The intermediate cyclic thiocarbonate is prepared from the reaction of 1, 2?diols with either benzenecarbothialdehyde one hand, it is assumed that the DBoreA Olefination proceeds via the attack of phosphite on sulfur, leading to an unstable carbene, which reacts with another phosphite to exclude carbon dioxide and produce the olefin. On the other hand, the reaction has also been claimed to undergo a concerted, cyclo-elimination mechanism.